tool call vis improvement

main.go

@@ -834,6 +834,7 @@ type Message struct {
   ReasoningContent string     `json:"reasoning_content,omitempty"`
   ToolCalls        []ToolCall `json:"tool_calls,omitempty"`
   ToolCallID       string     `json:"tool_call_id,omitempty"`
+  ToolCallsShown   bool       `json:"-"` // tool call headers already printed live during streaming
 }
 
 type ToolCall struct {
@@ -1133,6 +1134,53 @@ func parseStream(ctx context.Context, r io.Reader) (Message, Usage, error) {
   var lastUsage Usage
   tcs := map[int]*ToolCall{}
   var order []int
+  var toolCallsShown bool
+
+  // Progressive, per-token display of tool calls as they stream in, so the
+  // user watches the invocation being shaped token by token (like reasoning
+  // text) instead of a blank pause. Only used when stdout is a terminal;
+  // piped/redirected output is left untouched. Each fragment is appended
+  // directly to the terminal; the closing ")" is emitted only when the call is
+  // finalized, so the visible text is always a true prefix of the final form.
+  tty := isTerminal(int(os.Stdout.Fd()))
+  liveIdx := -1
+  livePrinted := ""
+  liveTarget := func(t *ToolCall, closed bool) string {
+    s := "[tool call: " + t.Function.Name
+    if closed || t.Function.Arguments != "" {
+      s += "(" + filterText(t.Function.Arguments)
+      if closed { s += ")]" }
+    }
+    return s
+  }
+  finishLive := func(closed bool) {
+    if liveIdx < 0 { return }
+    target := liveTarget(tcs[liveIdx], closed)
+    if len(target) > len(livePrinted) {
+      fmt.Print(c(target[len(livePrinted):], 33))
+    }
+    if closed { fmt.Print("\n") }
+    livePrinted = ""
+    liveIdx = -1
+  }
+  stepLive := func() {
+    if !tty || len(order) == 0 { return }
+    cur := order[len(order)-1]
+    if liveIdx != -1 && liveIdx != cur {
+      // A different tool call is now being shaped: finalize the previous one.
+      finishLive(true)
+    }
+    if liveIdx == -1 {
+      liveIdx = cur
+      livePrinted = ""
+    }
+    target := liveTarget(tcs[cur], false)
+    if len(target) > len(livePrinted) {
+      fmt.Print(c(target[len(livePrinted):], 33))
+      livePrinted = target
+    }
+    toolCallsShown = true
+  }
 
   flushTable := func() {
     if len(tblBuf) > 0 {
@@ -1199,16 +1247,32 @@ func parseStream(ctx context.Context, r io.Reader) (Message, Usage, error) {
         }
       }
     }
-    for _, tc := range dl.ToolCalls {
-      t, ok := tcs[tc.Index]
-      if !ok {
-        t = &ToolCall{Type: "function"}
-        tcs[tc.Index] = t
-        order = append(order, tc.Index)
+    if len(dl.ToolCalls) > 0 {
+      if inReasoning {
+        fmt.Print("\n" + c("--- reasoning end ---", 36) + "\n")
+        inReasoning = false
       }
-      if tc.ID != "" { t.ID = tc.ID }
-      if tc.Function.Name != "" { t.Function.Name += tc.Function.Name }
-      if tc.Function.Arguments != "" { t.Function.Arguments += tc.Function.Arguments }
+      if liveIdx == -1 {
+        // First tool call of the stream: flush any pending content line so it
+        // is not overwritten by the live tool-call line.
+        flushTable()
+        if lineBuf != "" {
+          fmt.Println(renderMDLine(lineBuf, &mdSt))
+          lineBuf = ""
+        }
+      }
+      for _, tc := range dl.ToolCalls {
+        t, ok := tcs[tc.Index]
+        if !ok {
+          t = &ToolCall{Type: "function"}
+          tcs[tc.Index] = t
+          order = append(order, tc.Index)
+        }
+        if tc.ID != "" { t.ID = tc.ID }
+        if tc.Function.Name != "" { t.Function.Name += tc.Function.Name }
+        if tc.Function.Arguments != "" { t.Function.Arguments += tc.Function.Arguments }
+      }
+      stepLive()
     }
   }
   if err := ctx.Err(); err != nil { return Message{}, lastUsage, err }
@@ -1221,10 +1285,15 @@ func parseStream(ctx context.Context, r io.Reader) (Message, Usage, error) {
       fmt.Println(renderMDLine(lineBuf, &mdSt))
     }
   }
+  if liveIdx >= 0 {
+    // Finalize the in-progress tool-call line so following output starts fresh.
+    finishLive(true)
+  }
   if inReasoning {
     fmt.Print("\n" + c("--- reasoning end ---", 36) + "\n")
   }
   m := Message{Role: "assistant"}
+  m.ToolCallsShown = toolCallsShown
   if content != "" { m.Content = strp(content) }
   if reas != "" { m.ReasoningContent = reas }
   if len(tcs) > 0 {
@@ -1393,7 +1462,9 @@ func AL(ctx context.Context, cfg *Cfg, msgs []Message) ([]Message, Usage, error)
     for _, tc := range m.ToolCalls {
       if err := ctx.Err(); err != nil { return msgs, turnUsage, err }
       fn, astr := tc.Function.Name, filterText(tc.Function.Arguments)
-      fmt.Println(c(fmt.Sprintf("[tool call: %s(%s)]", fn, astr), 33))
+      if !m.ToolCallsShown {
+        fmt.Println(c(fmt.Sprintf("[tool call: %s(%s)]", fn, astr), 33))
+      }
       res, sty := "", 2
       var a map[string]any
       if err := json.Unmarshal([]byte(astr), &a); err != nil || a == nil {